Guest Wifi on a different subnet?

Will be pretty hard to word things because i don't know the full picture as i just barged in half way through but i went to this company as an intern for study and the task is they want to set up a Wi-Fi guest network. They probably thought I'm a free cisco expert for some reason who would solve their issues right away.

There's Cisco 350x (192.168.255.254) as the main switch (which has a backup stacked) and the Aruba AP (192.168.255.84) which distributes the Wi-Fi company workers use.

There are several VLANs:

192.168.55.0 through 192.168.175.0 are used as subnets for different divisions (planning, soft dev etc.)

192.168.255.0 is the main Wi-Fi network which workers use for their devices through Aruba's AP device.

192.168.200.0 (specifically 192.168.200.100 ~ 192.168.200.200) <--- is reserved for guest wifi network.

I've double checked the windows 2016 server and DHCP server. The scopes seem to be written correctly.

The cisco DHCP server isn't used and is relayed. The VLANs are configured in the cisco interface.

Every other VLAN, aside from 200, has devices listed under Dynamic Addresses in the MAC Addresses Table tab in the cisco GUI.

I don't have enough knowledge about the ports, trunked, tagged and such and no idea if it comes to play.

---The task is to configure a guest AP with the range of 192.168.200.100~200 (and is it even possible to begin with since its a different subnet?)

The problem is that the win DHCP server doesn't want to give out ip addresses for 200.0 subnet since its different from 255.0 one and i cant seem to make it work. When i try to connect my phone via DHCP the ip for my phone is shown as 0.0.0.0 in the Aruba web interface.

If i set it to static and connect it, manages to connect but it says internet isn't available and there's no connection.

I've tried to set up the Aruba DHCP server but it just gives me "ip-range is too small or mis-aligned and can not be used with client count 250".

p.s. I have access to cisco 350x via terminal but I cant reboot it since all the work in the office will be halted